A known electric heater employs a coiled element attached to a source of electric current. As current is passed through the electric coil, it is heated and radiates energy. Also, the coil may be placed in the flow of air to transfer energy by conduction.
It is common to provide a support structure for holding the coiled heater element, and this structure typically includes a ceramic insulator which engages the heater coil and is attached to the support structure.
U.S. Pat. No. 4,363,959 (Cottrell et al.) shows an electric heater having a coiled heating element. The heating element is supported by insulators which are in turn attached to a frame. Several forms of the insulator are illustrated, and each relies upon a notch engaging an individual convolution of the heater coil. Embodiments shown in FIGS. 3, 4, and 5 employ slanted surfaces to direct adjacent convolutions of the heater coil into respective notches. FIG. 7 shows an embodiment wherein rounded ears direct convolutions into respective notches while another notch receives an intermediate convolution.
U.S. Pat. No. Des. 262,285 (Janning) discloses an insulator having upstanding ears and an intermediate broad notch. The upstanding ears form notches for receiving outer convolutions of a heater coil and an intermediate convolution is received in the central notch between the ears. Since this is a design patent, there is no disclosure regarding the operation of the device; however, it would appear that the rounded ears are intended to separate the convolutions of the heater coil during installation of the insulator.